Analysis by: Julie Anne Cabuhat
ALIASES:

Trojan-Ransom.Win32.Crypmodadv.xdi (Kaspersky), Trojan:Win32/Dynamer!ac (Microsoft)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size: 864,768 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 19 Nov 2016
Payload: Displays graphics/image, Encrypts files

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Other Details

This Trojan displays the following images:

It encrypts files with the following extensions:

  • .txt
  • .doc
  • .docx
  • .xls
  • .xlsx
  • .ppt
  • .pptx
  • .odt
  • .jpg
  • .png
  • .csv
  • .sql
  • .mdb
  • .sln
  • .php
  • .asp
  • .aspx
  • .html
  • .xml
  • .psd

NOTES:

Instead of using a server, this ransomware is capable of using a Pastebin feature to store the acquired GUID of the infected computer. In this feature, it uses the following URL:

  • http://{BLOCKED}in.com/api/api_post.php

It also uses the following API keys to send data:

  • api_dev_key
  • api_option
  • api_paste_code
  • api_paste_private
  • api_paste_name
  • api_paste_expire_date
  • api_paste_format
  • api_user_key

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.918.04
FIRST VSAPI PATTERN DATE: 19 Nov 2016
VSAPI OPR PATTERN File: 12.919.00
VSAPI OPR PATTERN Date: 20 Nov 2016

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Scan your computer with your Trend Micro product to delete files detected as RANSOM_VINDOWS.A. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.

Step 3

Restore encrypted files from backup.


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